/*
    Copyright 2012 Sven-Ove Bjerkan

    This file is part of KO-Ozi.

    KO-Ozi is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    KO-Ozi is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with KO-Ozi. If not, see <http://www.gnu.org/licenses/>.
     
    Source: http://tips4java.wordpress.com/2009/06/07/table-cell-listener/
*/

package com.koozi.ui.tracking;

import java.awt.event.ActionEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.Action;
import javax.swing.JTable;
import javax.swing.SwingUtilities;

/*
 * This class listens for changes made to the data in the table via the
 * TableCellEditor. When editing is started, the value of the cell is saved. When
 * editing is stopped the new value is saved. When the old and new values are
 * different, then the provided Action is invoked.
 *
 * The source of the Action is a TableCellListener instance.
 */
public class TableCellListener implements PropertyChangeListener, Runnable {

    private JTable table;
    private Action action;
    private int row;
    private int column;
    private Object oldValue;
    private Object newValue;

    /**
     * Create a TableCellListener.
     *
     * @param table the table to be monitored for data changes
     * @param action the Action to invoke when cell data is changed
     */
    public TableCellListener(JTable table, Action action) {
        this.table = table;
        this.action = action;
        this.table.addPropertyChangeListener(this);
    }

    /**
     * Create a TableCellListener with a copy of all the data relevant to the
     * change of data for a given cell.
     *
     * @param row the row of the changed cell
     * @param column the column of the changed cell
     * @param oldValue the old data of the changed cell
     * @param newValue the new data of the changed cell
     */
    private TableCellListener(JTable table, int row, int column, Object oldValue, Object newValue) {
        this.table = table;
        this.row = row;
        this.column = column;
        this.oldValue = oldValue;
        this.newValue = newValue;
    }

    /**
     * Get the column that was last edited
     *
     * @return the column that was edited
     */
    public int getColumn() {
        return column;
    }

    /**
     * Get the new value in the cell
     *
     * @return the new value in the cell
     */
    public Object getNewValue() {
        return newValue;
    }

    /**
     * Get the old value of the cell
     *
     * @return the old value of the cell
     */
    public Object getOldValue() {
        return oldValue;
    }

    /**
     * Get the row that was last edited
     *
     * @return the row that was edited
     */
    public int getRow() {
        return row;
    }

    /**
     * Get the table of the cell that was changed
     *
     * @return the table of the cell that was changed
     */
    public JTable getTable() {
        return table;
    }
//
//  Implement the PropertyChangeListener interface
//

    @Override
    public void propertyChange(PropertyChangeEvent e) {
        //  A cell has started/stopped editing

        if ("tableCellEditor".equals(e.getPropertyName())) {
            if (table.isEditing()) {
                processEditingStarted();
            } else {
                processEditingStopped();
            }
        }
    }

    /*
     * Save information of the cell about to be edited
     */
    private void processEditingStarted() {
        //  The invokeLater is necessary because the editing row and editing
        //  column of the table have not been set when the "tableCellEditor"
        //  PropertyChangeEvent is fired.
        //  This results in the "run" method being invoked

        SwingUtilities.invokeLater(this);
    }
    /*
     * See above.
     */

    @Override
    public void run() {
        row = table.convertRowIndexToModel(table.getEditingRow());
        column = table.convertColumnIndexToModel(table.getEditingColumn());
        oldValue = table.getModel().getValueAt(row, column);
        newValue = null;
    }

    /*
     * Update the Cell history when necessary
     */
    private void processEditingStopped() {
        newValue = table.getModel().getValueAt(row, column);
        if (newValue == null)
            newValue = "";
        if (oldValue == null)
            oldValue = "";

        //  The data has changed, invoke the supplied Action

        if (!newValue.equals(oldValue)) {
            //  Make a copy of the data in case another cell starts editing
            //  while processing this change

            TableCellListener tcl = new TableCellListener(
                    getTable(), getRow(), getColumn(), getOldValue(), getNewValue());

            ActionEvent event = new ActionEvent(
                    tcl,
                    ActionEvent.ACTION_PERFORMED,
                    "");
            action.actionPerformed(event);
        }
    }
}
